Containers may be produced by various processes including, plastic injection molding and/or blow molding techniques, metal stamping and drawing practices, and glass blank and blow molding processes. In the latter example, molten glass from a furnace is typically formed into glass containers in an efficient, large scale, commercial manufacturing process using an Individual Section (“I.S.”) machine. The molten glass is cut into uniform segments of glass called “gobs,” which are guided into blank molds. In each blank mold, a hot parison is formed, either by using a long plunger to push the glass into the blank mold, or by using a short, plunger and blowing the glass into conformity with the blank mold using gas passed through or around the plunger. The hot parison is then inverted and transferred to a blow mold, where the hot parison is blown into conformity with the blow mold in the shape of the container, and then is cooled to the point where it is sufficiently rigid to be gripped and removed from the blow mold. In general, a U.S. patent that illustrates an example of a process and equipment of this type includes U.S. Pat. No. 6,286,339.
More specifically, U.S. Pat. No. 9,440,761 discloses an example of a process and equipment for producing an internally threaded neck in a parison of a container. The equipment includes a plunger having a helical groove or rib on its outside surface, and a helical guide between the plunger and a thimble to transform linear movement by a linear actuator into roto-translational motion of the plunger. Although the process and equipment described in the '761 patent are commercially successful, the present disclosure provides further improvements.